The present invention relates generally to a magnetic head slider flying at a small distance above, or coming into intermittent contact with, the surface of a traveling recording medium and a magnetic disk drive. More specifically, the present invention relates to a magnetic head slider suitable for a magnetic disk drive using a small-diameter disk having a diameter of 45.7 mm (1.8 in.) or less.
The magnetic head slider is supported by a flexure attached to a suspension. The magnetic head slider flies at a small distance above, or comes into intermittent contact with, a magnetic disk to write and read data thereto and therefrom. Patent Document 1 (Japanese Patent Laid-Open No. 2003-123422) discloses the magnetic head slider that is currently widely used. FIG. 13 shows the construction of the conventional magnetic head slider disclosed in Patent Document 1. A medium opposing surface (bearing surface) 108 of a slider 101 includes three different kinds of surfaces: an air bearing surface 102 (102a, 102b, 102c), a shallowly grooved surface 104 (104a, 104b, 104c), and a deeply grooved surface 105. The shallowly grooved surface 104 includes a step slightly deeper than the air bearing surface 102. The deeply grooved surface 105 is a surface deeply grooved from the air bearing surface 102, even deeper than the shallowly grooved surface 104. The air bearing surface 102 includes a pair of right and left inflow side air bearing surfaces 102a, 102b and a center pad 102c. The pair of inflow side air bearing surfaces 102a, 102b are disposed on an air inflow side and in rear of the shallowly grooved surface 104. The center pad 102c is disposed on an air outflow end for mounting thereon a magnetic head 103. The shallowly grooved surface 104 includes a shallowly grooved surface 104a on the air inflow side, shallowly grooved rails 104b disposed on respective opposite sides, and a center pad shallowly grooved surface 104c. The center pad shallowly grooved surface 104c is disposed on the air inflow side of the center pad 102c. The deeply grooved surface 105 is substantially surrounded by the shallowly grooved surface 104a on the air inflow side, the inflow side air bearing surfaces 102a, 102b, and the shallowly grooved rails' 104b on the opposite sides. According to the construction of the magnetic head slider disclosed in Patent Document 1, the shallowly grooved surface 104a and the air bearing surfaces 102a, 102b provide a step air bearing function. This step air bearing function generates a lifting force causing the slider to fly above the magnetic disk. At the same time, the function produces a negative pressure on the deeply grooved surface 105. An appropriate air bearing stiffness is thus ensured to allow the slider to stably fly. The slider measures as follows: length Lx=1.25 mm; width Ly=1.0 mm; and height Lz=0.3 mm.
A recent trend in the magnetic disk drive is a shift toward a compact magnetic disk drive using a small-diameter disk to meet the need for high recording densities and with the aim of possible applications in compact digital equipment. Against this background, there is a problem of a decreasing effective data area on the surface of a circular disk. As an approach to solving this problem, there is known a method for reducing the slider in size. There has been developed a compact slider representing about 70% in dimensions of the aforementioned slider that is currently widely used. FIG. 14 is a plan view showing a compact slider. A slider 101 measures as follows: length Lx=0.85 mm; width Ly=0.7 mm; and height Lz=0.23 mm. This compact slider 101 results in the effective data area of the disk being widened by 0.3 mm. This can translate to a substantial improvement for a compact magnetic disk drive with a disk size of 25.4 mm (1 in.) or 20.3 mm (0.8 in.)
In addition, a reduction in size of the slider, or a reduction in a slider width and a slider height in particular, can almost double the number of sliders that can be taken from the same wafer size using the same magnetic head fabrication equipment. This yields a benefit of a reduced slider cost.
Conventionally, slider processing processes flow as described below. Specifically, bearing surfaces are lapped of a bar of about 40 sliders arranged in a horizontal row. The bearing surfaces are then formed through a dry process, such as ion milling or the like. The bar is then cut into individual sliders through chip cutting. Burrs and chipping therefore occur on the sides of the sliders from chip cutting. A protrusion with a height of more than 0.2 μm can occur on the side of the air bearing surface at these portions having the burrs and chips. There has therefore been a problem involved with extending the air bearing surface to both ends in the direction of slider width. The problem includes the burrs and chips impeding a stable flying action, which damages the disk, thus substantially degrading reliability.
In addition, stress relaxation occurs during chip cutting, which causes local deformation to occur at a chip cutting portion of a bearing surface 108. The profile is a recess having both ends protruding on the side of the recording medium. Local deformation can particularly be noticed on both sides of the slider. This local deformation causes fluctuations in a flying characteristic, impeding an approach toward a lower flying height and a stabled flying action. The local deformation also leads to damage to the circular disk due to possible contact during loading/unloading. The conventional process therefore defies extension of the air bearing surface up to side ends. A 30-μm-wide shallowly grooved surface 109 is provided on each of both ends of the inflow side air bearing surfaces 102a, 102b. A 30 μm-wide cutting margin portion 110 having the same depth as the deeply grooved surface 105 is provided on an outside of the 30 μm-wide shallowly grooved surface 109. A length L2 from the air bearing surface end to the slider end is 60 μm. A length L1 from the air bearing surface end to the shallowly grooved surface is 30 μm.